[PATCH v2 2/6] iio: light: stk3310: Implement vdd supply and power it off during suspend

[Aren Moynihan]

From: Ondrej Jirman <m...@xff.cz>

VDD power input can be used to completely power off the chip during
system suspend. Do so if available.

Signed-off-by: Ondrej Jirman <m...@xff.cz>
Signed-off-by: Aren Moynihan <a...@peacevolution.org>
---

Notes:
    Changes in v2:
     - always enable / disable regulators and rely on a dummy regulator if
       one isn't specified
     - replace usleep_range with fsleep
     - reorder includes so iio headers are last
     - add missing error handling to resume

 drivers/iio/light/stk3310.c | 49 ++++++++++++++++++++++++++++++++++---
 1 file changed, 46 insertions(+), 3 deletions(-)

diff --git a/drivers/iio/light/stk3310.c b/drivers/iio/light/stk3310.c
index 7b71ad71d78d..a0547eeca3e3 100644
--- a/drivers/iio/light/stk3310.c
+++ b/drivers/iio/light/stk3310.c
@@ -13,6 +13,8 @@
 #include <linux/module.h>
 #include <linux/mod_devicetable.h>
 #include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+
 #include <linux/iio/events.h>
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
@@ -117,6 +119,7 @@ struct stk3310_data {
        struct regmap_field *reg_int_ps;
        struct regmap_field *reg_flag_psint;
        struct regmap_field *reg_flag_nf;
+       struct regulator *vdd_reg;
 };
 
 static const struct iio_event_spec stk3310_events[] = {
@@ -607,6 +610,10 @@ static int stk3310_probe(struct i2c_client *client)
 
        mutex_init(&data->lock);
 
+       data->vdd_reg = devm_regulator_get(&client->dev, "vdd");
+       if (IS_ERR(data->vdd_reg))
+               return dev_err_probe(&client->dev, ret, "get regulator vdd 
failed\n");
+
        ret = stk3310_regmap_init(data);
        if (ret < 0)
                return ret;
@@ -617,9 +624,17 @@ static int stk3310_probe(struct i2c_client *client)
        indio_dev->channels = stk3310_channels;
        indio_dev->num_channels = ARRAY_SIZE(stk3310_channels);
 
+       ret = regulator_enable(data->vdd_reg);
+       if (ret)
+               return dev_err_probe(&client->dev, ret,
+                                    "regulator vdd enable failed\n");
+
+       /* we need a short delay to allow the chip time to power on */
+       fsleep(1000);
+
        ret = stk3310_init(indio_dev);
        if (ret < 0)
-               return ret;
+               goto err_vdd_disable;
 
        if (client->irq > 0) {
                ret = devm_request_threaded_irq(&client->dev, client->irq,
@@ -645,32 +660,60 @@ static int stk3310_probe(struct i2c_client *client)
 
 err_standby:
        stk3310_set_state(data, STK3310_STATE_STANDBY);
+err_vdd_disable:
+       regulator_disable(data->vdd_reg);
        return ret;
 }
 
 static void stk3310_remove(struct i2c_client *client)
 {
        struct iio_dev *indio_dev = i2c_get_clientdata(client);
+       struct stk3310_data *data = iio_priv(indio_dev);
 
        iio_device_unregister(indio_dev);
        stk3310_set_state(iio_priv(indio_dev), STK3310_STATE_STANDBY);
+       regulator_disable(data->vdd_reg);
 }
 
 static int stk3310_suspend(struct device *dev)
 {
        struct stk3310_data *data;
+       int ret;
 
        data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
 
-       return stk3310_set_state(data, STK3310_STATE_STANDBY);
+       ret = stk3310_set_state(data, STK3310_STATE_STANDBY);
+       if (ret)
+               return ret;
+
+       regcache_mark_dirty(data->regmap);
+       regulator_disable(data->vdd_reg);
+
+       return 0;
 }
 
 static int stk3310_resume(struct device *dev)
 {
-       u8 state = 0;
        struct stk3310_data *data;
+       u8 state = 0;
+       int ret;
 
        data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
+
+       ret = regulator_enable(data->vdd_reg);
+       if (ret) {
+               dev_err(dev, "Failed to re-enable regulator vdd\n");
+               return ret;
+       }
+
+       fsleep(1000);
+
+       ret = regcache_sync(data->regmap);
+       if (ret) {
+               dev_err(dev, "Failed to restore registers: %d\n", ret);
+               return ret;
+       }
+
        if (data->ps_enabled)
                state |= STK3310_STATE_EN_PS;
        if (data->als_enabled)
-- 
2.44.0